Characterization of specific egg yolk immunoglobulin (IgY) against mastitis-causing Staphylococcus aureus

Monoclonal Antibodies as a Therapeutic Strategy against Multidrug-Resistant Bacterial Infections in a Post-COVID-19 Era

The development of severe multidrug-resistant bacterial infections has recently intensified because of the COVID-19 pandemic. According to the guidelines issued by the World Health Organization (WHO), routine antibiotic administration is not recommended for patients with supposed or confirmed mild SARS-CoV-2 infection or pneumonia, unless bacterial infection is clinically suspected. However, recent studies have pointed out that the proportion of non-essential antibiotic use in patients infected with SARS-CoV-2 remains high. Therefore, the silent pandemic of antibiotic resistance remains a pressing issue regardless of the present threats presented by the COVID-19 pandemic. To prevent or delay entry into the postulated post-antibiotic era, the long-term advocacy for the rational use of antibiotics, the optimization of infection control procedures, and the development of new antibacterial agents and vaccines should be underscored as vital practices of the antibacterial toolbox. Recently, the development of vaccines and monoclonal antibodies has gradually received attention following the advancement of biotechnology as well as enhanced drug discovery and development in cancer research. Although decent progress has been made in laboratory-based research and promising results have been obtained following clinical trials of some of these products, challenges still exist in their widespread clinical applications. This article describes the current advantages of antibacterial monoclonal antibodies, the development of associated clinical trials, and some perceived future perspectives and challenges. Further, we anticipate the development of more therapeutic agents to combat drug-resistant bacterial infections as well as to increase the resilience of current or novel agents/strategies.

IgYs: on her majesty's secret service

There has been an increasing interest in using Immunoglobulin Y (IgY) antibodies as an alternative to "classical" antimicrobials. Unlike traditional antibiotics, they can be utilized on a continual basis without leading to the development of resistance. The veterinary IgY antibody market is growing because of the demand for minimal antibiotic use in animal production. IgY antibodies are not as strong as antibiotics for treating infections, but they work well as preventative agents and are natural, nontoxic, and easy to produce. They can be administered orally and are well tolerated, even by young animals. Unlike antibiotics, oral IgY supplements support the microbiome that plays a vital role in maintaining overall health, including immune system function. IgY formulations can be delivered as egg yolk powder and do not require extensive purification. Lipids in IgY supplements improve antibody stability in the digestive tract. Given this, using IgY antibodies as an alternative to antimicrobials has garnered interest. In this review, we will examine their antibacterial potential.

Feasibility of avian antibodies as prophylaxis against enterotoxigenic escherichia coli colonization

Background

This research aims to evaluate the feasibility of using avian immunoglobulins (IgY) raised against adhesion factors of enterotoxigenic Escherichia coli (ETEC) as prophylaxis of diarrheal illness caused by these pathogens. ETEC requires adhesion to human intestinal epithelial cells as a primary step in establishing enteric infection. Therefore, inhibition of adhesion may prevent such infections and reduce clinical burdens of diarrheal illness.

Methods

IgY samples were prepared from eggs of hens immunized with an adhesin-tip multiepitope fusion antigen (MEFA), developed against nine adhesin tip epitopes derived from clinically relevant ETEC strains. The resulting IgY was evaluated for its ability to inhibit adhesion of ETEC to cell-surface targets. Potential impacts of anti-MEFA IgY on growth of both pathogenic and commensal E. coli isolates were also evaluated.

Results

Enzyme linked immunosorbent assay (ELISA) titers were achieved for IgY targeting each of the nine individual epitopes included in the adhesin-tip MEFA. Furthermore, anti-MEFA titers exceeding 1:2¹⁹ were sustained for at least 23 weeks. All ETEC strains used in design of the adhesin-tip MEFA, and five of five clinical ETEC strains were significantly (P < 0.05) inhibited from adhesion to mammalian cells in culture.

Conclusions

These findings demonstrate that IgY targeting ETEC adhesin-tip MEFA have the potential to disrupt in vitro adherence of ETEC. A formulation containing adhesin-tip MEFA IgY can be considered a potential candidate for in vivo evaluation as prophylaxis of diarrheal diseases. Animal studies of this formulation are planned.

Chicken IgY reduces the risk of Pseudomonas aeruginosa urinary tract infections in a murine model

Introduction

Urinary tract infections (UTIs) with Pseudomonas aeruginosa are a severe problem in disposed patients in modern healthcare. Pseudomonas aeruginosa establishes recalcitrant biofilm infections and can develop antibiotic resistance. Gargling with avian egg yolk anti-Pseudomonas antibodies (IgY) has shown clinical effect in preventing onset of chronic P. aeruginosa lung infections in patients with cystic fibrosis (CF). Therefore, we speculated whether passive intravesically administered IgY immunotherapy could be a novel strategy against P. aeruginosa UTIs.

Aim

To evaluate if prophylactic repurposing of anti-Pseudomonas IgY can prevent UTIs with P. aeruginosa in a UTI mouse model.

Materials and methods

In vitro, P. aeruginosa (PAO1 and PAO3) was mixed with increasing concentrations of specific anti-Pseudomonas IgY (sIgY) or non-specific control IgY (cIgY) and/or freshly isolated human neutrophils. Bacterial growth was evaluated by the optical density at 600 nm. In vivo, via a temporary transurethral catheter, 10-week-old female Balb/c mice were intravesically infected with 50 ml of a bacterial suspension and sIgY, cIgY, or isotonic NaCl. IgY and NaCl were either co-instilled with the bacteria, or instilled prophylactically, 30 min prior to infection. The animals were euthanized 20 h after infection. Vesical bacteriology was quantified, and cytokine expression in the bladder homogenate was measured by multiplex cytokine assay.

Results

In vitro, sIgY concentrations above 2.5% reduced bacterial growth in a dose-dependent manner. In vivo, a UTI lasting for minimum 7 days was established by installing 5 × 106 colony-forming units (CFU) of P. aeruginosa PAO1. sIgY reduced vesical bacterial load if co-installed with P. aeruginosa PAO1. Prophylactic sIgY and cIgY reduced bacterial load when compared to isotonic NaCl. CXCL2 and G-CSF were both increased in infected bladders compared to non-infected controls which had non-detectable levels. Co-installation of sIgY and bacteria nearly completely inhibited the inflammatory response. However, the cytokine levels in the bladder did not change after prophylactic administration of sIgY or cIgY.

Conclusion

Prophylactic sIgY significantly reduces the amount of bacteria in the bladder in a mouse model of P. aeruginosa cystitis and may serve as a novel non-antibiotic strategy in preventing P. aeruginosa UTIs.

Anti-Staphylococcus aureus Single-Chain Fragment Variables Play a Protective Anti-Inflammatory Role In Vitro and In Vivo

Staphylococcus aureus is a causative agent of bovine mastitis, capable of causing significant economic losses to the dairy industry worldwide. This study focuses on obtaining single-chain fragment variables (scFvs) against the virulence factors of S. aureus and evaluates the protective effect of scFvs on bovine mammary epithelial (MAC-T) cells and mice mammary gland tissues infected by S. aureus. After five rounds of bio-panning, four scFvs targeting four virulence factors of S. aureus were obtained. The complementarity-determining regions (CDRs) of these scFvs exhibited significant diversities, especially CDR3 of the VH domain. In vitro, each of scFvs was capable of inhibiting S. aureus growth and reducing the damage of MAC-T cells infected by S. aureus. Preincubation of MAC-T cells with scFvs could significantly attenuate the effect of apoptosis and necrosis compared with the negative control group. In vivo, the qPCR and ELISA results demonstrated that scFvs reduced the transcription and expression of Tumor Necrosis Factor alpha (TNF-α), interleukin-1β (IL-1β), IL-6, IL-8, and IL-18. Histopathology and myeloperoxidase (MPO) results showed that scFvs ameliorated the histopathological damages and reduced the inflammatory cells infiltration. The overall results demonstrated the positive anti-inflammatory effect of scFvs, revealing the potential role of scFvs in the prevention and treatment of S. aureus infections.

Immunoglobulin Y for Potential Diagnostic and Therapeutic Applications in Infectious Diseases

Antiviral, antibacterial, and antiparasitic drugs and vaccines are essential to maintaining the health of humans and animals. Yet, their production can be slow and expensive, and efficacy lost once pathogens mount resistance. Chicken immunoglobulin Y (IgY) is a highly conserved homolog of human immunoglobulin G (IgG) that has shown benefits and a favorable safety profile, primarily in animal models of human infectious diseases. IgY is fast-acting, easy to produce, and low cost. IgY antibodies can readily be generated in large quantities with minimal environmental harm or infrastructure investment by using egg-laying hens. We summarize a variety of IgY uses, focusing on their potential for the detection, prevention, and treatment of human and animal infections.

Avian antibodies (IgY) targeting spike glycoprotein of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) inhibit receptor binding and viral replication

BACKGROUND

The global pandemic of Coronavirus infectious disease 2019 (COVID-19), caused by SARS-CoV-2, has plunged the world into both social and economic disarray, with vaccines still emerging and a continued paucity of personal protective equipment; the pandemic has also highlighted the potential for rapid emergence of aggressive respiratory pathogens and the need for preparedness. Avian immunoglobulins (IgY) have been previously shown in animal models to protect against new infection and mitigate established infection when applied intranasally. We carried out a proof-of-concept study to address the feasibility of using such antibodies as mucosally-applied prophylaxis against SARS-CoV-2.

METHODS

Hens were immunized with recombinant S1 spike glycoprotein of the virus, and the resulting IgY was evaluated for binding specificity, inhibition of glycoprotein binding to angiotensin converting enzyme-2 (ACE2) protein (the requisite binding site for the virus), and inhibition of viral replication in Vero cell culture.

RESULTS

Titers of anti-S1 glycoprotein IgY were evident in yolks at 14 days post-immunization, peaking at 21 days, and at peak concentrations of 16.8 mg/ml. IgY showed strong and significant inhibition of S1/ACE2 binding interactions, and significantly inhibited viral replication at a concentration of 16.8 mg/ml. Four weeks' collection from eggs of two hens produced a total of 1.55 grams of IgY.

CONCLUSIONS

In this proof-of-concept study we showed that avian immunoglobulins (IgY) raised against a key virulence factor of the SARS-CoV-2 virus successfully inhibited the critical initial adhesion of viral spike glycoproteins to human ACE2 protein receptors and inhibited viral replication in vitro, in a short period using only two laying hens. We conclude that production of large amounts of IgY inhibiting viral binding and replication of SARS-CoV-2 is feasible, and that incorporation of this or similar material into an intranasal spray and/or other mucosal protecting products may be effective at reducing infection and spread of COVID-19.

Anti-PcrV IgY antibodies protect against Pseudomonas aeruginosa infection in both acute pneumonia and burn wound models

Pseudomonas aeruginosa is a common nosocomial pathogen in burn patients, and rapidly acquires antibiotic resistance; thus, developing an effective therapeutic approach is the most promising strategy for combating infection. Type III secretion system (T3SS) translocates bacterial toxins into the cytosol of the targeted eukaryotic cells, which plays important roles in the virulence of P. aeruginosa infections in both acute pneumonia and burn wound models. The PcrV protein, a T3SS translocating protein, is required for T3SS function and is a well-validated target in animal models of immunoprophylactic strategies targeting P. aeruginosa. In the present study, we evaluated the protective efficacy of chicken egg yolk antibodies (IgY) raised against recombinant PcrV (r-PcrV) in both acute pneumonia and burn wound models. R-PcrV protein was generated by expressing the pcrV gene (cloned in pET-28a vector) in E. coli BL-21. Anti-PcrV IgY was obtained by immunization of hen. Anti-PcrV IgY induced greater protection in P. aeruginosamurine acute pneumonia and burn wound models than control IgY (C-IgY) and PBS groups. Anti-PcrV IgY improved opsonophagocytic killing and inhibition of bacterial invasion of host cells. Taken together, our data provide evidence that anti-PcrV IgY can be a promising therapeutic candidate for combating P. aeruginosa infections.

Preparation and identification of chicken egg yolk immunoglobulins against human enterovirus 71 for diagnosis of hand-foot-and-mouth disease

Human enterovirus 71 (EV71) is one of the major pathogens that causes hand-foot-and mouth disease, and there is an urgent need for rapid diagnosis of EV71 virus infection for early antiviral treatment. The aim of this study was to prepare chicken egg yolk immunoglobulin Y (IgY) for the diagnosis of enterovirus type 71 infection. The antibodies were raised by intramuscular immunization of laying hens with inactivated human EV71 and isolated from the egg yolk by multiple steps of polyethylene glycol 6000 extraction. The average concentration of IgY antibody was 26.60 mg/mL during the whole immunization. After the first immunization, the IgY titer gradually increased, and reached the peak on the 55th days. Meanwhile, the use of western blotting test demonstrated that specific IgY binds specifically to capsid proteins VP2 and VP3 of EV71 virus. Furthermore, a facile one-step method based on turn-on fluorescence sensing was developed by using IgY antibodies, which can detect EV71 virus at low concentrations of 10⁴ PFU/mL and was 94.44% coincidence with RT-PCR in 30 clinical samples. These findings indicate that EV71-IgY antibodies are an easily prepared and rich source of antibodies that offers a potential alternative strategy for routine screening of EV71 infection.

The preparation and therapeutic roles of scFv-Fc antibody against Staphylococcus aureus infection to control bovine mastitis

Staphylococcus aureus-induced bovine mastitis causes significant losses to the dairy industry and available vaccines do not confer adequate protection. As a more attractive alternative, we propose the use of antibody (Ab) therapy. In our previous study, we constructed a bovine single-chain variable fragment (scFv) Ab phage display and successfully obtained scFvs that bound to S. aureus antigens with high affinity. Here, we describe a novel Ab against S. aureus (scFv-Fc Ab). To construct the scFv-Fc Ab, the scFv Ab was genetically fused to the Fc fragment of a bovine IgG1 Ab. Western blot analysis showed that the bovine scFvs-Fc Abs were successfully expressed with horseradish peroxidase-conjugated goat-anti-bovine IgG (Fc) Ab in Escherichia coli cells. The purified bovine scFvs-Fc Abs had good binding activity to S. aureus and effectively inhibited the bacterial growth in culture medium and bovine scFvs-Fc Abs enhanced phagocytosis of S. aureus by neutrophils isolated from peripheral blood in a dose-dependent manner. In the experiment of bovine scFvs-Fc Abs for the treatment of S. aureus-induced bovine mastitis, the total effective percentage reached 82% (9/11). These novel bovine scFvs-Fc Abs may be useful as therapeutic candidates for the prevention and treatment of S. aureus-induced bovine mastitis.

Identification of a novel mechanism of action of bovine IgG antibodies specific for Staphylococcus aureus

Staphylococcus aureus is a major pathogen that causes subclinical mastitis associated with huge economic losses to the dairy industry. A few vaccines for bovine mastitis are available, and they are expected to induce the production of S. aureus-specific antibodies that prevent bacterial adherence to host cells or promote opsonization by phagocytes. However, the efficacy of such vaccines are still under debate; therefore, further research focusing on improving the current vaccines by seeking additional mechanisms of action is required to reduce economic losses due to mastitis in the dairy industry. Here, we generated S. aureus-specific bovine IgG antibodies (anti-S. aureus) that directly inhibited bacterial growth in vitro. Inhibition depended on specificity for anti-S. aureus, not the interaction between Protein A and the fragment crystallizable region of the IgG antibodies or bacterial agglutination. An in vitro culture study using S. aureus strain JE2 and its deletion mutant JE2ΔSrtA, which lacks the gene encoding sortase A, revealed that the effect of anti-S. aureus was sortase-A-independent. Sortase A is involved in the synthesis of cell-wall-associated proteins. Thus, other surface molecules, such as membrane proteins, cell surface polysaccharides, or both, may trigger the inhibition of bacterial growth by anti-S. aureus. Together, our findings contribute insights into developing new strategies to further improve the available mastitis vaccine by designing a novel antigen on the surface of S. aureus to induce inhibitory signals that prevent bacterial growth.

Effects of specific egg yolk immunoglobulin on pan-drug-resistant Acinetobacter baumannii

With the growing emergence of pan-drug-resistant Acinetobacter baumannii (PDR-Ab) strains in clinical, new strategies for the treatment of PDR-Ab infections are urgently needed. Egg yolk immunoglobulin (IgY) as a convenient and inexpensive antibody has been widely applied to the therapy of infectious diseases. The aim of this study was to produce IgY specific to PDR-Ab and investigate its antibacterial effects in vitro and in vivo. IgYs specific to two PDR-Ab strains were produced by immunizing hens with formaldehyde inactivated PDR-Ab cells and isolated from yolks with a purity of 90% by water dilution, salt precipitations and ultrafiltration. IgYs showed high titers when subjected to an ELISA and inhibited the growth of PDR-Ab in a dose-dependent manner in liquid medium. Scanning electron microscopy assay showed structural modification and aggregation of PDR-Ab treated with specific IgYs. Freshly cultured PDR-Ab cells were nasally inhaled in BALB/c mice to induce acute pneumonia. The infected mice were intraperitoneally injected with specific IgYs using cefoperazone/sulbactam and dexamethasone as positive controls. The IgYs specific to PDR-Ab lowered the mortality of mice with PDR-Ab-induced acute pneumonia, decreased the level of TNF-α and IL-1β in serum and reduced inflammation in lung tissue. Specific IgY has the potential to be used as a new therapeutic approach for the treatment of A. baumannii-induced infections.

Method for generation of peptide-specific IgY antibodies directed to Staphylococcus aureus extracellular fibrinogen binding protein epitope

The IgY antibodies offer an attractive alternative to mammalian IgGs in research, diagnosis and medicine. The isolation of immunoglobulin Y from the egg yolks is efficient and economical, causing minimal suffering to animals. Here we present the methodology for the production of IgY antibodies specific to Staphylococcus aureus fibrinogen binding protein (Efb) and its peptidyl epitope (spanning residues 127-140). The Efb is an extracellular, adhesion protein which binds both human fibrinogen and complement C3 protein thus contributing to the high infectious potential of this pathogen. The selected epitope of Efb protein is responsible for the interaction with C3. The immunochemical characterization of both anti-Efb and epitope-specific IgY antibodies revealed their similar avidity, titer, and reactivity profile, although some differences in the hen's immune response to administered antigens is discussed.

Chicken egg yolk antibodies (IgY) modulate the intestinal mucosal immune response in a mouse model of Salmonella typhimurium infection

This study determined the effects of chicken egg yolk antibodies (IgY) on immune responses in the intestinal mucosal of mice infected with Salmonella typhimurium. Sixty, 28-day-old mice were divided into 4 groups and treated with streptomycin or sterile water for 2 days followed by 1 day without treatment. The control group was unchallenged whereas the mice in the other three groups were treated twice with 10⁹ CFU mL^− 1S. typhimurium. For the next 3 days, control mice continued to receive no treatment whereas the mice in the remaining three groups were orally administered with 20 mg mL^− 1 of specific IgY, 20 mg mL^− 1 of nonspecific IgY or PBS. S. typhimurium activated gut-associated lymphoid tissue, increasing the release of IFN-γ and TNF-α in the mucosa and increased the number of activated T-lymphocytes and cytotoxic T-γδ. Specific IgY attenuated the increase in IFN-γ and TNF-α and the decrease in IL-10. S. typhimurium induced mobilization of CD8⁺ and CD8⁺ TCRγδ T cells in the epithelium and CD4⁺ and CD8⁺ T cells in the lamina propria reflecting an inflammatory process that was attenuated by IgY. These results suggest that specific IgY modulates intestinal mucosal immune responses during a S. typhimurium infection.

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Specific IgY could effectively alleviate S. typhimurium-inflicted damage to the jejunum.

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Specific IgY attenuated an increase in the cytokines IFN-γ and TNF-α in the mucosa.

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IgY attenuated changes in lymphocyte numbers in Peyer's patches, epithelium and lamina propria.

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Specific IgY has an important immune-modulatory role on the intestinal mucosal immune response.

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Specific IgY limits the consequences of intestinal inflammation induced by S. typhimurium.

Anti-Pseudomonas aeruginosa IgY antibodies promote bacterial opsonization and augment the phagocytic activity of polymorphonuclear neutrophils

Moderation of polymorphonuclear neutrophils (PMNs) as part of a critical defense against invading pathogens may offer a promising therapeutic approach to supplement the antibiotic eradication of Pseudomonas aeruginosa infection in non-chronically infected cystic fibrosis (CF) patients. We have observed that egg yolk antibodies (IgY) harvested from White leghorn chickens that target P. aeruginosa opsonize the pathogen and enhance the PMN-mediated respiratory burst and subsequent bacterial killing in vitro. The effects on PMN phagocytic activity were observed in different Pseudomonas aeruginosa strains, including clinical isolates from non-chronically infected CF patients. Thus, oral prophylaxis with anti-Pseudomonas aeruginosa IgY may boost the innate immunity against Pseudomonas aeruginosa in the CF setting by facilitating a rapid and prompt bacterial clearance by PMNs.

Bovine-associated CNS species resist phagocytosis differently

Background

Coagulase-negative staphylococci (CNS) cause usually subclinical or mild clinical bovine mastitis, which often remains persistent. Symptoms are usually mild, mostly only comprising slight changes in the appearance of milk and possibly slight swelling. However, clinical mastitis with severe signs has also been reported. The reasons for the differences in clinical expression are largely unknown. Macrophages play an important role in the innate immunity of the udder. This study examined phagocytosis and killing by mouse macrophage cells of three CNS species: Staphylococcus chromogenes (15 isolates), Staphylococcus agnetis (6 isolates) and Staphylococcus simulans (15 isolates). Staphylococcus aureus (7 isolates) was also included as a control.

Results

All the studied CNS species were phagocytosed by macrophages, but S. simulans resisted phagocytosis more effectively than the other CNS species. Only S. chromogenes was substantially killed by macrophages. Significant variations between isolates were seen in both phagocytosis and killing by macrophages and were more common in the killing assays. Significant differences between single CNS species and S. aureus were observed in both assays.

Conclusion

This study demonstrated that differences in the phagocytosis and killing of mastitis-causing staphylococci by macrophages exist at both the species and isolate level.

Chicken egg yolk antibody (IgY) controls Solobacterium moorei under in vitro and in vivo conditions

Solobacterium moorei is a causative agent in diseases such as oral halitosis, bacteremia, and necrobacillosis-associated thrombophlebitis. The objective of this study was to determine the effectiveness of chicken egg yolk antibody (IgY) in controlling S. moorei. Intact S. moorei cells were used as an immunogen to immunize four White Leghorn laying hens. IgY, extracted from egg yolks obtained from these immunized hens, was purified using water dilution, two-step salt precipitation, and ultrafiltration. The purity of the IgY obtained was approximately 87.3 %. The antibody titer of the IgY was determined by enzyme-linked immunosorbent assay. The antibody titer peaked at 10,000 following the third immunization. In order to evaluate the inhibitory effects of the specific IgY, the growth of S. moorei in liquid media was measured every 12 h using a microplate reader at 600 nm. Biofilm formation of S. moorei was quantified by staining with crystal violet. The specific binding ability of IgY was further confirmed by the use of immunofluorescence and immunoelectron microscopy. Growth and biofilm formation of S. moorei were significantly (P<0.05) inhibited by 20 and 40 mg/ml specific IgY compared with the control. The specific IgY also decreased the bacterial level in the oral cavity of mice after infection with S. moorei. This study demonstrates that the growth and biofilm formation of S. moorei can be effectively inhibited by specific IgY. As a result, IgY technology may have application in the control of diseases caused by S. moorei.

Growth inhibition of Staphylococcus aureus and escherichia coli strains by neutralizing IgY antibodies from ostrich egg yolk

Ostrich raising around the world have some key factors and farming profit depend largely on information and ability of farmers to rear these animals. Non fertilized eggs from ostriches are discharged in the reproduction season. Staphylococcus aureus and Escherichia coli are microorganisms involved in animal and human diseases. In order to optimize the use of sub products of ostrich raising, non fertilized eggs of four selected birds were utilized for development of polyclonal IgY antibodies. The birds were immunized (200ug/animal) with purified recombinant staphylococcal enterotoxin C (recSEC) and synthetic recRAP, both derived from S. aureus, and recBFPA and recEspB involved in E. coli pathogenicity, diluted in FCA injected in the braquial muscle. Two subsequent immunization steps with 21 days intervals were repeated in 0,85% saline in FIA. Blood and eggs samples were collected before and after immunization steps. Egg yolk immunoglobulins were purified by precipitation with 19% sodium sulfate and 20% ammonium sulphate methodologies. Purified IgY 50μL aliquots were incubated in 850μL BHI broth containing 50μL inoculums of five strains of S. aureus and five strains of E.coli during four hours at 37°C. Growth inhibition was evaluated followed by photometry reading (DO550nm). Egg yolk IgY preparation from hiperimmunized birds contained antibodies that inhibited significantly (p<0,05) growth of strains tested. Potential use of ostrich IgY polyclonal antibodies as a diagnostic and therapeutic tool is proposed for diseased animals.

Preparation and characterization of egg yolk immunoglobulin Y specific to influenza B virus

The aim of this study was to prepare egg yolk immunoglobulin (IgY) for use in the prevention and treatment of influenza B viral infections. Laying hens were immunized with inactivated influenza B virus (IBV), and IgY was isolated from the egg yolk by multiple polyethylene glycol (PEG) 6000 extraction and ammonium sulfate purification steps. The titers and specificity of the purified antibodies were assessed. The specific IgY titer increased beginning the second week after the first immunization, with the titer peaking at the fifth week. The yield of IgY was 76.5mg per yolk, and the purity was 98.2%. The use of western blotting and the hemagglutination inhibition (HI) test demonstrated that IBV-specific IgY binds specifically to influenza B virus proteins, and a plaque reduction assay revealed the neutralization efficacy of IBV-specific IgY at reducing influenza infection in MDCK cells. Furthermore, when mice were treated intranasally prior to or after influenza B virus infection, IBV-specific IgY protected the mice from influenza infection or reduced viral replication in their lungs, respectively. These findings indicate that IgY is an easily prepared and rich source of antibodies that offers a potential alternative strategy for preventing and treating influenza B infections.

Application of chicken egg yolk immunoglobulins in the control of terrestrial and aquatic animal diseases: a review

Oral administration of chicken egg yolk immunoglobulin (IgY) has attracted considerable attention as a means of controlling infectious diseases of bacterial and viral origin. Oral administration of IgY possesses many advantages compared with mammalian IgG including cost-effectiveness, convenience and high yield. This review presents an overview of the potential to use IgY immunotherapy for the prevention and treatment of terrestrial and aquatic animal diseases and speculates on the future of IgY technology. Included are a review of the potential application of IgY for the treatment of livestock diseases such as mastitis and diarrhea, poultry diseases such as Salmonella, Campylobacteriosis, infectious bursal disease and Newcastle disease, as well as aquatic diseases like shrimp white spot syndrome virus, Yersina ruckeri and Edwardsiella tarda. Some potential obstacles to the adoption of IgY technology are also discussed.